Aluminum Fiberglass Dewars

Vapor shielded aluminum fiberglass is the most popular style for bucket dewars. This style dewar fills fastest and requires no liquid nitrogen maintenance. 'Belly' options are available to increase the liquid helium volume. The epoxy fiberglass necks have helium gas diffusion barriers. The highest efficiency is obtained by a combination of 'hard' shields and multiple 'soft' (foil) shields, located in the insulating vacuum space.